1. Field of the Invention
The present invention relates to communication navigation systems and methods, etc. for performing navigation by transmitting map data to navigation terminals via a communication network. More particularly, the invention is directed to a communication navigation system and method, etc. which does not complicate the system and which can easily take care of updated navigation terminals.
2. Description of Related Art
Various types of navigation systems have been proposed, which perform navigation by transmitting map data and route guidance information from a server, via computer and mobile communications networks including the Internet, to various types of navigation terminals, such as in-vehicle navigation units, portable navigation units, PDAs (Personal Digital Assistants) and cellular telephones, according to their request. Each of these navigation terminals presents a user with predetermined information visibly and audibly, based on position data detected by a GPS (Global Positioning System) receiver mounted thereon as well as map data and route guidance information transmitted from the server, to guide the user to his or her destination.
In these communication navigation systems, the route guidance information transmitted from the server plays an important role in guiding the user to his or her destination, together with the map data. However, each navigation terminal accepts only a type of route guidance information which is uniquely compatible with itself. For example, a navigation terminal may be updated to perform a guidance step by using some items of route guidance information which the navigation terminal as unupdated could not have processed. In addition, it would be user-friendly if some unnecessary route guidance information can be omitted visibly and/or audibly from a navigation terminal.
An object of the invention is to provide a communication navigation system and method, etc. which does not complicate the system and which can easily take care of updated navigation terminals through flexible control, when each of the navigation terminals involved accepts only such route guidance information as being uniquely compatible with itself.
A first aspect of the invention provides a communication navigation system that performs navigation, using map data stored in a map database site and current position data about navigation terminals, by transmitting the map data to the navigation terminals via a communication network. The communication navigation system is provided with: a route guidance information transmitting device which transmits items of route guidance information to each of the navigation terminals via the communication network; a determining device, provided at each of the navigation terminals, which determines whether or not the items of route guidance information transmitted by the route guidance information transmitting device are necessary; and a guidance device which performs guidance using only one or more items of route guidance information determined to be necessary by the determining device.
According to this communication navigation system, only items of route guidance information determined to be necessary by the determining device are used to implement guidance. Thus, even when each navigation terminal accepts only items of route guidance information uniquely compatible therewith, the route guidance information transmitting device no longer needs to process the information differently for each navigation terminal. A skipping device may be provided so that if the determining means determines that a current one of the items of route guidance information is not necessary, the processing of the current one of the items of route guidance information is skipped to cause the determining device to determine whether or not a next one of the items of route guidance information is necessary. In this case, the current one of the items of route guidance information may not be read by skipping as many bytes as its data size.
The communication navigation system may be provided with an input device which accepts an input of one or more items of route guidance information to be determined to be necessary by the determining device.
In this case, the guidance device can bypass a guidance step based on any item of route guidance information which the user thinks is unnecessary. The input device may be used so that the user can enter one or more items of route guidance information which he or she thinks are necessary or unnecessary.
Another aspect of the invention provides a communication navigation method for performing navigation, using map data stored in a map database site and current position data about navigation terminals, by transmitting the map data to the navigation terminals via a communication network. The communication navigation method is provided with: a route guidance information transmitting process for transmitting items of route guidance information to each of the navigation terminals via the communication network; a determining process, performed by each of the navigation terminals, for determining whether or not the items of route guidance information transmitted by the route guidance information transmitting process are necessary; and a guidance process for performing guidance using only one or more items of route guidance information determined to be necessary by the determining process.
According to this communication navigation method, only items of route guidance information determined to be necessary by the determining process are used to implement guidance. Thus, even when each navigation terminal accepts only items of route guidance information uniquely compatible therewith, the route guidance information transmitting process no longer needs to process the information differently for each navigation terminal. A skipping process may be provided so that if the determining process determines that a current one of the items of route guidance information is not necessary, the processing of the current one of the items of route guidance information is skipped to cause the determining process to determine whether or not a next one of the items of route guidance information is necessary. In this case, the current one of the items of route guidance information may not be read by skipping as many bytes as its data size.
The communication navigation method may be provided with an input process for accepting an input of one or more items of route guidance information to be determined to be necessary by the determining process.
In this case, the guidance means can bypass a guidance step based on any item of route guidance information which the user thinks is unnecessary. The input process may be used so that the user can enter one or more items of route guidance information which he or she thinks are necessary or unnecessary.
Still another aspect of the invention provides a terminal unit that executes a communication navigation method for performing navigation, using map data stored in a map database site and current position data about navigation terminals, by transmitting the map data to the navigation terminals via a communication network. The terminal unit is provided with: a determining device which determines whether or not the items of route guidance information transmitted by a route guidance information transmitting device are necessary, the route guidance information transmitting device in the map database site, which transmits items of route guidance information to each of the navigation terminals via the communication network; and a guidance device which performs guidance using only one or more items of route guidance information determined to be necessary by the determining device.
According to this terminal unit, only items of route guidance information determined to be necessary by the determining device are used to implement guidance. Thus, even when each navigation terminal accepts only items of route guidance information uniquely compatible therewith, the route guidance information transmitting device no longer needs to process the information differently for each navigation terminal. A skipping device may be provided so that if the determining procedure determines that a current one of the items of route guidance information is not necessary, the processing of the current one of the items of route guidance information is skipped to cause the determining device to determine whether or not a next one of the items of route guidance information is necessary. In this case, the current one of the items of route guidance information may not be read by skipping as many bytes as its data size.
The terminal unit may be provided with an input device for accepting an input of one or more items of route guidance information to be determined to be necessary by the determining device.
In this case, the guidance device can bypass a guidance step based on any item of route guidance information which the user thinks is unnecessary. The input device may be used so that the user may enter one or more items of route guidance information which he or she thinks are necessary or unnecessary.
Yet another aspect of the invention provides a route guidance information transmitting device that executes a communication navigation method for performing navigation, using map data stored in a map database site and current position data about navigation terminals, by transmitting the map data to the navigation terminals via a communication network, wherein the route guidance information transmitting device which transmits items of route guidance information to each of the navigation terminals via the communication network, the navigation terminals comprising: a determining device for determining whether or not the items of route guidance information transmitted by the route guidance information transmitting device are necessary; and a guidance device for performing guidance using only one or more items of route guidance information determined to be necessary by the determining device
According to this route guidance information transmitting device, only items of route guidance information determined to be necessary by the determining device are used to implement guidance. Thus, even when each navigation terminal accepts only items of route guidance information uniquely compatible therewith, the route guidance information transmitting device no longer needs to process the information differently for each navigation terminal. A skipping device may be provided so that if the determining device determines that a current one of the items of route guidance information is not necessary, the processing of the current one of the items of route guidance information is skipped to cause the determining device to determine whether or not a next one of the items of route guidance information is necessary. In this case, the current one of the items of route guidance information may not be read by skipping as many bytes as its data size.